A free app for Android, by V Vorld.

File to PDF Converter is an easy-to-use application that allows you to convert your file to PDF format without the need to upload it to a server. It can convert many file extensions like Adobe Illustrator(Ai), Adobe Photoshop(PSD), CorelDraw(CDR), DWG, DOCX, PPTX, EPUB, EPS, PNG, BMP, JPEG/JPG, and Camera raw file formats like ari, 3fr, cr2, crw, kdc, sr2, dng, erf, orf, mrw & many more)

It is very easy to install and user-friendly.

You can choose the file extension like Adobe Illustrator(Ai) then the application will list all the files available on your mobile device that matches the extension selected by the user.